The present invention relates to data communication in a computer network. More particularly, the present invention relates to improved methods and apparatus for permitting a client computer in a client-server architecture computer network to exchange media commands and media data with the server using the HTTP (hypertext transfer protocol) protocol.
Client-server architectures are well known to those skilled in the computer art. For example, in a typical computer network, one or more client computers may be coupled to any number of server computers. Client computers typically refer to terminals or personal computers through which end users interact with the network. Server computers typically represent nodes in the computer network where data, application programs, and the like, reside. Server computers may also represent nodes in the network for forwarding data, programs, and the likes from other servers to the requesting client computers.
To facilitate discussion, FIG. 1 illustrates a computer network 100, representing for example a subset of an international computer network popularly known as the Internet. As is well known, the Internet represents a well-known international computer network that links, among others, various military, governmental, educational, nonprofit, industrial and financial institutions, commercial enterprises, and individuals. There are shown in FIG. 1 a server 102, a server 104, and a client computer 106. Server computer 104 is separated from client computer 106 by a firewall 108, which may be implemented in either software or hardware, and may reside on a computer and/or circuit between client computer 106 and server computer 104.
Firewall 108 may be specified, as is well known to those skilled in the art, to prevent certain types of data and/or protocols from traversing through it. The specific data and/or protocols prohibited or permitted to traverse firewall 108 depend on the firewall parameters, which are typically set by a system administrator responsible for the maintenance and security of client computer 106 and/or other computers connected to it, e.g., other computers in a local area network. By way of example, firewall 108 may be set up to prevent TCP, UDP, or HTTP (Transmission Control Protocol, User Datagram Protocol, and Hypertext Transfer Protocol, respectively) data and/or other protocols from being transmitted between client computer 106 and server 104. The firewalls could be configured to allow specific TCP or UDP sessions, for example outgoing TCP connection to certain ports, UDP sessions to certain ports, and the like.
Without a firewall, any type of data and/or protocol may be communicated between a client computer and a server computer if appropriate software and/or hardware are employed. For example, server 102 resides on the same side of firewall 108 as client computer 106, i.e., firewall 108 is not disposed in between the communication path between server 102 and client computer 106. Accordingly, few, if any, of the protocols that client computer 106 may employ to communicate with server 102 may be blocked.
As is well known to those skilled in the art, some computer networks may be provided with proxies, i.e., software codes or hardware circuitries that facilitate the indirect communication between a client computer and a server around a firewall. With reference to FIG. 1, for example, client computer 106 may communicate with server 104 through proxy 120. Through proxy 120, HTTP data, which may otherwise be blocked by firewall 108 for the purpose of this example, may be transmitted between client computer 106 and server computer 104.
In the prior art, the HTTP protocol is typically employed to transmit web pages between the client computer and the server computer. As is well known to those skilled, the HTTP protocol, as specified by for example the Internet Request For Comments RFC 1945 (T. Berners-Lee et al.), typically defines only three types of requests to be sent from the client computer to the server, namely GET, POST, and HEAD. The POST command, for instance, is specified in RFC 1945 to be composed of a Request-Line, one or more Headers and Entity-Body.
In some cases, it may be desirable, however, to employ the HTTP protocol to communicate other types of commands and receive other types of data between the client computer and the server computer. By way of example, in applications such as real-time or live video streaming, the HTTP protocol may represent, on some networks, the most advantageous protocol available for use in transmitting and receiving data. This is because, for example, there may exists firewalls or other network limitations that inhibit the use of other protocols for transmitting media control commands and for receiving media data. Media control commands may represent, for example, commands to fast forward on the play stream, to seek backward on the play stream, to begin playing at a certain frame, to stop, to pause, and the like. Media data may represent, for example, real-time or live video, audio, or annotation data. In these cases, the ability to use the HTTP protocol to transmit media commands and to receive media data may indeed be valuable.
In view of the foregoing, there are desired improved techniques for permitting a client computer in a client-server architecture computer network to exchange media commands and media a data with the server computer using the HTTP (hypertext transfer protocol) protocol.